{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-76840", "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "state": "PUBLISHED", "assignerShortName": "VulnCheck", "dateReserved": "2026-08-19T20:34:19.724Z", "datePublished": "2026-08-24T13:11:58.408Z", "dateUpdated": "2026-10-01T15:21:11.754Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "shortName": "VulnCheck", "dateUpdated": "2026-10-01T15:21:11.754Z" }, "datePublic": "2026-08-18T00:00:00.000Z", "title": "RustDesk through 1.4.9 Heap Buffer Overflow via Unvalidated CLIPRDR FileContentsResponse Length", "descriptions": [ { "lang": "en", "value": "RustDesk's Windows clipboard redirection copies a peer-supplied length into a fixed-size caller buffer without an upper bound check. When an OLE paste consumer such as explorer.exe calls IStream::Read with a buffer of cb bytes, CliprdrStream_Read in libs/clipboard/src/windows/wf_cliprdr.c requests that many bytes of a remote file through cliprdr_send_request_filecontents and then executes CopyMemory(pv, clipboard->req_fdata, clipboard->req_fsize), where req_fsize is taken verbatim from the peer's CLIPRDR FileContentsResponse by wf_cliprdr_server_file_contents_response (req_fsize = fileContentsResponse->cbRequested) and is never clamped to cb anywhere in the chain. The function's only length comparison, req_fsize < cb, handles the short-read case and is evaluated after the copy has already occurred. A malicious or compromised peer that answers a small file-contents read with an oversized response therefore writes attacker-chosen data past the end of the paste consumer's heap buffer when the local user pastes clipboard file contents offered by the remote side. The file is a fork of FreeRDP's client/Windows/wf_cliprdr.c, where the same defect is CVE-2026-68579, fixed in FreeRDP 3.30.0." } ], "problemTypes": [ { "descriptions": [ { "lang": "en", "cweId": "CWE-787", "description": "Out-of-bounds Write", "type": "CWE" } ] }, { "descriptions": [ { "lang": "en", "cweId": "CWE-20", "description": "Improper Input Validation", "type": "CWE" } ] } ], "affected": [ { "vendor": "rustdesk", "product": "rustdesk", "collectionURL": "https://github.com/rustdesk/rustdesk", "packageName": "rustdesk", "defaultStatus": "unaffected", "versions": [ { "version": "0", "lessThanOrEqual": "1.4.9", "status": "affected", "versionType": "semver" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:a:rustdesk:rustdesk:*:*:*:*:*:*:*:*", "versionEndIncluding": "1.4.9" } ] } ] } ], "metrics": [ { "format": "CVSS", "cvssV4_0": { "version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:L/SI:H/SA:H", "baseScore": 8.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "PASSIVE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "LOW", "subIntegrityImpact": "HIGH", "subAvailabilityImpact": "HIGH" } }, { "format": "CVSS", "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:H", "baseScore": 9.6, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "CHANGED", "confidentialityImpact": "LOW", "integrityImpact": "HIGH", "availabilityImpact": "HIGH" } } ], "references": [ { "url": "https://github.com/rustdesk/rustdesk", "tags": [ "product" ] }, { "url": "https://github.com/rustdesk/rustdesk/blob/1.4.9/libs/clipboard/src/windows/wf_cliprdr.c", "tags": [ "technical-description" ] }, { "url": "https://github.com/rustdesk/rustdesk/pull/15515", "tags": [ "issue-tracking", "patch" ] }, { "url": "https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-m37j-jcr2-8gcc", "name": "GitHub Security Advisory (GHSA-m37j-jcr2-8gcc)", "tags": [ "third-party-advisory" ] }, { "name": "VulnCheck Advisory: RustDesk through 1.4.9 Heap Buffer Overflow via Unvalidated CLIPRDR FileContentsResponse Length", "tags": [ "third-party-advisory" ], "url": "https://www.vulncheck.com/advisories/rustdesk-through-heap-buffer-overflow-via-unvalidated-cliprdr-filecontentsresponse-length" } ], "credits": [ { "lang": "en", "value": "Michael Holmquist", "type": "finder" } ], "x_generator": { "engine": "vulncheck-endgame" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "timestamp": "2026-08-24T16:26:40.462428Z", "id": "CVE-2026-76840", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "role": "CISA Coordinator", "version": "2.0.3" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-08-24T16:27:03.717Z" } } ] } }